After deciding that I was going to finally spring for an exhaust for my car, I found that the one I'd settled on is on backorder for a month or two. So, instead of waiting for it to come back in stock, I went ahead and pulled the trigger on something else I'd been wanting to do ever since I got the car: delete the primary cats and get a tune.
Gains are impressive; can't wait to feel (and hear) the difference.
Details (company is BPM Sport):
E9X M3 Performance Engine Software Stage II Tune + ACM Test Pipes (Package Deal)
Reprogrammed ignition timing, & optimization of fuel quality: 91 Octane (damn you, Oklahoma)
Startup changes: Variable RPM limit based on engine temp, warm up
Limiters: Removed top speed limiter, Raised RPM limit
Servotronic Steering Changes: Yes
Raised Rev limit to: 8600 RPM
BPM Sport Launch Assist: Enabled: 4000 RPM
DME software update: 240E DME Software update